The invention relates to a method for measuring a presence of a high voltage at a high-voltage component fitted in a vehicle. The method can be used, in particular, for establishing the absence of voltage on the vehicle.
Vehicles can nowadays have components which operate on a high voltage so that there is a high voltage present at these components in a switched-on state. For reasons of occupant safety, it is critical to be able to check at any time whether a high voltage is present in the vehicle. For example, it is possible to establish whether the vehicle is free of voltage potential prior to performing any work on the vehicle. Only in this way is it possible to ensure that a mechanic, whilst performing repair work on the vehicle, or a development engineer in a development and/or test phase of the vehicle, is warned against inadvertently touching a high voltage which is present.
Some vehicles have a built-in diagnostic system for this purpose, which diagnostic system is connected to the high-voltage components and checks for the presence of a high voltage. However, it is not always possible to be able to rely on this diagnostic system. For example, the diagnostic system could operate in an unreliable manner in various stages of the development process of the vehicle or the diagnostic system could have been damaged as a result of an accident or a defect, with the result that both a development engineer during testing and a mechanic during repair work on the vehicle cannot always rely on the indications of the diagnostic system.
One object of the present invention therefore is to overcome the above-mentioned disadvantages of the diagnostic system. A further object is to provide a method which makes it possible to be able to check for the presence of a high voltage at a high-voltage component at any time and/or to establish the absence of voltage.
These and other objects are achieved by a method for indicating a presence of a high voltage at a high-voltage component equipped in a vehicle. This method comprises the following steps: connecting an external reader to a communications bus of the vehicle; outputting a signal by way of the high-voltage component or by way of a component control unit, which is connected to the high-voltage component, to the communications bus, wherein the signal indicates whether a high voltage is present at the high-voltage component; and reading the signal from the communications bus by way of the external reader.
The signal which is output by the high-voltage component or by the component control unit, which is connected to the high-voltage component, to the communications bus can indicate the value of the voltage present at the high-voltage component.
The read signal can be displayed by the external reader. The external reader can read and display a plurality of signals of different components.
Correspondingly, the signal which indicates a presence of a high voltage is output by the high-voltage component or by a component control unit, which identifies a presence of a high voltage at the high-voltage component.
For this purpose, the high-voltage component at which a high voltage could be present can be connected directly to the communications bus and can transmit a signal to the communications bus which indicates whether a high voltage is present at the high-voltage component at that time.
As an alternative to this, the vehicle can have a component control unit, which is assigned to the high-voltage component, wherein the high-voltage component is not itself connected to the communications bus. Instead, the component control unit is connected to the communications bus. The component control unit can identify whether a high voltage is present at the high-voltage component and can output a corresponding signal with this information to the communications bus.
In particular, the signal output by the high-voltage component or by the component control unit can be the signal with which the high-voltage component or the component control unit also communicates with the diagnostic system. Correspondingly, no modifications to the high-voltage component or the component control unit are required for the inventive method.
In contrast to a communication with the diagnostic system, the external reader makes it possible to communicate directly on a component level with the high-voltage component or with a component control unit, which is connected to the high-voltage component. Even when the diagnostic system should not function, the high-voltage component or the component control unit will nevertheless output the corresponding signal to the communications bus, so that communication with the external reader remains possible. Correspondingly, the reliability of the check for a presence of a high voltage at a high-voltage component is increased. As a result, the operational safety, for example for a mechanic during repair work on a vehicle or a development engineer during development of the vehicle, can be decisively increased.
The signal is now read by an external reader as an alternative to or in addition to reading by the built-in diagnostics system. The term “external” should in this case be understood to mean that the reader is not built into the vehicle. The reader is accordingly not a permanent part of the vehicle. The reader can instead be connected to a connection of the communications bus, which is built into the vehicle. In order to connect the external reader, therefore, no modification to the vehicle is required. Instead, the communications bus which is used for the communication between the high-voltage component and the diagnostic system can also be used for communication with the external reader.
The connection of the communications bus can be a connection which is provided as standard in a test vehicle. The connection of the communications bus can alternatively be a connection which is installed as a one-off. In addition, the connection of the communications bus can be a temporary connection. As an alternative to this, the connection of the communications bus can be a connection which is provided in any vehicle. The term “any vehicle” should in this case be understood to mean that it is not a test vehicle but a standard vehicle.
In addition, the inventive method has the advantage that the structure of the vehicle does not need to be modified or influenced. In order to connect the external reader, for example, no additional holes need to be incorporated in the vehicle body. Correspondingly, the crash behavior of the vehicle is not impaired by the method.
The external reader is a small handy device which can display the output signal which indicates a presence of a high voltage.
In this case, the method is not restricted to one high-voltage component. Instead, a plurality of high-voltage components or a plurality of component control units, which each output a signal which indicates whether a high voltage is present at the respective high-voltage component, can be connected to the communications bus.
In addition, the method can include the step of outputting a warning signal by the external reader if a high voltage is present at the high-voltage component. As a result, a development engineer or a mechanic can be warned of the presence of a high voltage in good time. The warning signal may be, for example, an audible or visual signal.
In addition, the reader can have a display screen, on which the read signal is displayed. Correspondingly, it is possible to identify directly on the display screen whether a high voltage is present at one of the high-voltage components of a vehicle.
The communications bus can be a controller area network (CAN) bus system or another communications bus.
The vehicle can have an electric drive. In particular in the case of vehicles with an electric drive, components which require a high voltage are present. The components may be, for example, the battery of the vehicle or components of the drive electronics of the vehicle.
The external reader can be suitable for use in different vehicles. For this purpose, the external reader can have a menu from which a user can select the respective vehicle to whose communications bus the external reader is connected.
The method described herein can be used to establish whether the vehicle is free of voltage potential.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawing.